1. Field of the Invention
The invention relates generally to a new nonwoven material which, when employed as a surface web or sheet or in addition to the surface web as a strip in the crotch region in an absorbent article of hygiene, such as a diaper or dressing for an incontinent person, permits a better isolation of the user's skin from the absorbent part of the article of hygiene.
2. Discussion of Related Art
Absorbent articles of hygiene such as diapers and dressings for incontinent persons generally comprise an outer layer made of material which is impervious to body fluids, a pad or mat of absorbent material and a surface web or sheet which is permeable to body fluids such as urine, of size and shape which are similar to those of the impervious outer layer of the article. This surface web which is permeable to body fluids is intended to isolate the skin from the moistened absorbent pad. Consequently, the surface web must have a suitable degree of softness and must ensure a desired isolation between the skin and the absorbent pad. The function of the absorbent pad is to absorb the fluids and consequently it must have a high rate of absorption as well as a high absorption capacity. A particularly effective absorbent pad is described in document EP-A-0,232,729. This absorbent pad or mat is made up of a sheet of long absorbent fibers lined on its faces with a layer of cellulose wadding. The sheet lined with the layers of wadding is needled from both faces.
A particularly effective mat described in this Patent Application EP-A-0,232,729 comprises two sheets of long fibers, a first sheet of absorbent fibers and a second sheet of nonabsorbent fibers, between which particles of superabsorbent material are arranged, the sheet of nonabsorbent fibers being lined externally with a layer of nonwoven and the sheet of absorbent fibers being lined externally with a layer of cellulose wadding. The whole is bonded by needling from both faces.
In absorbent articles of hygiene such absorbent mats or pads are covered with a surface web generally made of nonwoven material, the purpose of which is to isolate the skin from the absorbent pad and which must ensure a pleasant contact with the skin and the desired isolation with the absorbent pad. These surface webs or sheets must exhibit, as essential properties, a pleasant contact with the skin, a high rate of passage by the body fluids and must form a barrier against rewetting.
Document FR-A-2,588,285 describes a multilayer nonwoven textile which has at least two layers of nonwoven web, one of the layers consisting of fibers of bilobed cross-section and the other layer consisting of fibers of trilobed cross-section. Each web layer is preferably obtained by the spin-bonding technique and the two web layers are joined to form the multilayer nonwoven by heat bonding in compacted and noncontinuous regions.
Document WO 87/07,117 describes an absorbent article of hygiene comprising an absorbent body surrounded by a cover. This cover or surface web consists of two layers made of nonwoven material. The first layer of nonwoven material, in contact with the user's skin, consists of a thin layer of spin-bonded fibrous tissue made of a hydrophobic material, and the second layer in contact with the absorbent body is a hydrophobic fibrous layer of fiber tissue, which is melt-bonded, similar in construction to the first layer. These two layers of surface web are not joined together in the region intended to come into contact with the user's body.
Document WO 88/05,269 relates to a surface web for a disposable absorbent article made up of at least two layers of nonwoven, which may be identical or different and which are joined by lines of adhesive forming an open pattern.